Considerations on the Management of Acute Postoperative Ischemia After Cardiac Surgery: A Scientific Statement From the American Heart Association.

Acute postoperative myocardial ischemia (PMI) after cardiac surgery is an infrequent event that can evolve rapidly and become a potentially life-threatening complication. Multiple factors are associated with acute PMI after cardiac surgery and may vary by the type of surgical procedure performed. Although the criteria defining nonprocedural myocardial ischemia are well established, there are no universally accepted criteria for the diagnosis of acute PMI. In addition, current evidence on the management of acute PMI after cardiac surgery is sparse and generally of low methodological quality. Once acute PMI is suspected, prompt diagnosis and treatment are imperative, and options range from conservative strategies to percutaneous coronary intervention and redo coronary artery bypass grafting. In this document, a multidisciplinary group including experts in cardiac surgery, cardiology, anesthesiology, and postoperative care summarizes the existing evidence on diagnosis and treatment of acute PMI and provides clinical guidance.

Graft Failure After Coronary Artery Bypass Grafting and Its Association With Patient Characteristics and Clinical Events: A Pooled Individual Patient Data Analysis of Clinical Trials With Imaging Follow-Up.

BACKGROUND: Graft patency is the postulated mechanism for the benefits of coronary artery bypass grafting (CABG). However, systematic graft imaging assessment after CABG is rare, and there is a lack of contemporary data on the factors associated with graft failure and on the association between graft failure and clinical events after CABG. METHODS: We pooled individual patient data from randomized clinical trials with systematic CABG graft imaging to assess the incidence of graft failure and its association with clinical risk factors. The primary outcome was the composite of myocardial infarction or repeat revascularization occurring after CABG and before imaging. A 2-stage meta-analytic approach was used to evaluate the association between graft failure and the primary outcome. We also assessed the association between graft failure and myocardial infarction, repeat revascularization, or all-cause death occurring after imaging. RESULTS: Seven trials were included comprising 4413 patients (mean age, 64.4±9.1 years; 777 [17.6%] women; 3636 [82.4%] men) and 13 163 grafts (8740 saphenous vein grafts and 4423 arterial grafts). The median time to imaging was 1.02 years (interquartile range [IQR], 1.00-1.03). Graft failure occurred in 1487 (33.7%) patients and in 2190 (16.6%) grafts. Age (adjusted odds ratio [aOR], 1.08 [per 10-year increment] [95% CI, 1.01-1.15]; P=0.03), female sex (aOR, 1.27 [95% CI, 1.08-1.50]; P=0.004), and smoking (aOR, 1.20 [95% CI, 1.04-1.38]; P=0.01) were independently associated with graft failure, whereas statins were associated with a protective effect (aOR, 0.74 [95% CI, 0.63-0.88]; P<0.001). Graft failure was associated with an increased risk of myocardial infarction or repeat revascularization occurring between CABG and imaging assessment (8.0% in patients with graft failure versus 1.7% in patients without graft failure; aOR, 3.98 [95% CI, 3.54-4.47]; P<0.001). Graft failure was also associated with an increased risk of myocardial infarction or repeat revascularization occurring after imaging (7.8% versus 2.0%; aOR, 2.59 [95% CI, 1.86-3.62]; P<0.001). All-cause death after imaging occurred more frequently in patients with graft failure compared with patients without graft failure (11.0% versus 2.1%; aOR, 2.79 [95% CI, 2.01-3.89]; P<0.001). CONCLUSIONS: In contemporary practice, graft failure remains common among patients undergoing CABG and is strongly associated with adverse cardiac events.

Unanswered questions on coronary artery graft patency and clinical outcomes.

PURPOSE OF REVIEW: To review current issues related to coronary artery graft patency and outcomes. RECENT FINDINGS: The association of coronary artery graft patency with clinical outcomes is a traditional concept; however, it has been challenged by the results of numerous studies. Key limitations of the existing evidence include the lack of a universal definition of graft failure, the absence of systematic imaging in contemporary coronary artery bypass grafting trials, the reliance on observational data with inherent selection and survival bias, and high attrition rates for follow-up imaging. Key modulators of graft failure, and of the relationship between graft failure and outcomes, include the type of conduit and myocardial territory grafted, conduit harvesting technique, and postoperative antithrombotic regimen and patient sex. SUMMARY: The relationship between graft failure and clinical events is complex and variable. Overall, the preponderance of current data suggests a possible association between graft failure and nonfatal clinical events.

Antiplatelet therapy around CABG: the latest evidence.

PURPOSE OF REVIEW: The optimal antiplatelet strategy in patients after coronary artery bypass graft (CABG) surgery is unclear. We review the evidence on the efficacy and safety of DAPT after CABG and discuss potential novel antiplatelet strategies that reduce the risk of bleeding without loss of efficacy. RECENT FINDINGS: Adding the potent P2Y12 inhibitor ticagrelor to aspirin for 1 year after CABG is associated with a reduction in the risk of vein graft failure, at the expense of an increased risk of clinically important bleeding. Ticagrelor monotherapy is not associated with better efficacy than aspirin alone, but is not associated with increased bleeding risk. SUMMARY: Dual antiplatelet therapy (DAPT) is recommended after acute coronary syndrome events, but aspirin as single antiplatelet therapy remains the cornerstone of antithrombotic therapy in stable ischemic heart disease because of a lack of solid evidence on the benefit of DAPT on clinical outcomes. Shorter duration DAPT, based on the pathophysiology of vein graft failure, may be a promising strategy that requires testing in adequately powered randomized trials.

Coronary Artery Bypass Surgery to Treat Anomalous Origin of Coronary Arteries in Adults: A Systematic Review.

OBJECTIVE: To review the available literature on the use of coronary artery bypass grafting (CABG) as a treatment option for anomalous origin of coronary artery in adults. METHODS: A systematic literature search was performed in March 2023 (including Ovid MEDLINE, Ovid Embase, and the Cochrane Library databases) to identify studies reporting the use of CABG in adult patients with anomalous origin of coronary artery. RESULTS: A total of 31 studies and 62 patients were included, 32 patients (52%) were women, and the mean age was 45.1±16.1 years. The most common coronary anomaly was the right coronary artery arising from the left coronary sinus in 26 patients (42%), followed by an anomalous left coronary artery from the pulmonary artery in 23 patients (37%). A total of 65 conduits were used in 61 patients, and 1 case report did not report conduit type. Reported grafts included saphenous vein (23 of 65 [35.4%]), left internal thoracic artery (15 of 65 [23.1%]), right internal thoracic artery (23 of 65 [35.4%]), and radial artery (2 of 65 [3.1%]); right gastroepiploic artery and basilic vein were used once (1.5%) each. Ligation of the native coronary artery was performed in 42 (67.7%) patients. Patient follow-up was available in 19 studies with a mean of 31.2 months. Only 1 operative mortality was reported. CONCLUSIONS: Based on the limited available data, CABG can be performed with good early results. Use of arterial conduits and ligation of the native coronary artery may improve long-term graft patency.

The Use of Intraoperative Transit Time Flow Measurement for Coronary Artery Bypass Surgery: Systematic Review of the Evidence and Expert Opinion Statements.

Transit time flow measurement (TTFM) allows quality control in coronary artery bypass grafting but remains largely underused, probably because of limited information and the lack of standardization. We performed a systematic review of the evidence on TTFM and other methods for quality control in coronary artery bypass grafting following PRISMA standards and elaborated expert recommendations by using a structured process. A panel of 19 experts took part in the consensus process using a 3-step modified Delphi method that consisted of 2 rounds of electronic voting and a final face-to-face virtual meeting. Eighty percent agreement was required for acceptance of the statements. A 2-level scale (strong, moderate) was used to grade the statements based on the perceived likelihood of a clinical benefit. The existing evidence supports an association between TTFM readings and graft patency and postoperative clinical outcomes, although there is high methodological heterogeneity among the published series. The evidence is more robust for arterial, rather than venous, grafts and for grafts to the left anterior descending artery. Although TTFM use increases the duration and the cost of surgery, there are no data to quantify this effect. Based on the systematic review, 10 expert statements for TTFM use in clinical practice were formulated. Six were approved at the first round of voting, 3 at the second round, and 1 at the virtual meeting. In conclusion, although TTFM use may increase the costs and duration of the procedure and requires a learning curve, its cost/benefit ratio seems largely favorable, in view of the potential clinical consequences of graft dysfunction. These consensus statements will help to standardize the use of TTFM in clinical practice and provide guidance in clinical decision-making.

The association between coronary graft patency and clinical status in patients with coronary artery disease.

The concept of a direct association between coronary graft patency and clinical status is generally accepted. However, the relationship is more complex and variable than usually thought. Key issues are the lack of a common definition of graft occlusion and of a standardized imaging protocol for patients undergoing coronary bypass surgery. Factors like the type of graft, the timing of the occlusion, and the amount of myocardium at risk, as well as baseline patients' characteristics, modulate the patency-to-clinical status association. Available evidence suggests that graft occlusion is more often associated with non-fatal events rather than death. Also, graft failure due to competitive flow is generally a benign event, while graft occlusion in a graft-dependent circulation is associated with clinical symptoms. In this systematic review, we summarize the evidence on the association between graft status and clinical outcomes.

Association of Dual Antiplatelet Therapy With Ticagrelor With Vein Graft Failure After Coronary Artery Bypass Graft Surgery: A Systematic Review and Meta-analysis.

Importance: The role of ticagrelor with or without aspirin after coronary artery bypass graft surgery remains unclear. Objective: To compare the risks of vein graft failure and bleeding associated with ticagrelor dual antiplatelet therapy (DAPT) or ticagrelor monotherapy vs aspirin among patients undergoing coronary artery bypass graft surgery. Data Sources: MEDLINE, Embase, and Cochrane Library databases from inception to June 1, 2022, without language restriction. Study Selection: Randomized clinical trials (RCTs) comparing the effects of ticagrelor DAPT or ticagrelor monotherapy vs aspirin on saphenous vein graft failure. Data Extraction and Synthesis: Individual patient data provided by each trial were synthesized into a combined data set for independent analysis. Multilevel logistic regression models were used. Main Outcomes and Measures: The primary analysis assessed the incidence of saphenous vein graft failure per graft (primary outcome) in RCTs comparing ticagrelor DAPT with aspirin. Secondary outcomes were saphenous vein graft failure per patient and Bleeding Academic Research Consortium (BARC) type 2, 3, or 5 bleeding events. A supplementary analysis included RCTs comparing ticagrelor monotherapy with aspirin. Results: A total of 4 RCTs were included in the meta-analysis, involving 1316 patients and 1668 saphenous vein grafts. Of the 871 patients in the primary analysis, 435 received ticagrelor DAPT (median age, 67 years [IQR, 60-72 years]; 65 women [14.9%]; 370 men [85.1%]) and 436 received aspirin (median age, 66 years [IQR, 61-73 years]; 63 women [14.5%]; 373 men [85.5%]). Ticagrelor DAPT was associated with a significantly lower incidence of saphenous vein graft failure (11.2%) per graft than was aspirin (20%; difference, -8.7% [95% CI, -13.5% to -3.9%]; OR, 0.51 [95% CI, 0.35 to 0.74]; P < .001) and was associated with a significantly lower incidence of saphenous vein graft failure per patient (13.2% vs 23.0%, difference, -9.7% [95% CI, -14.9% to -4.4%]; OR, 0.51 [95% CI, 0.35 to 0.74]; P < .001). Ticagrelor DAPT (22.1%) was associated with a significantly higher incidence of BARC type 2, 3, or 5 bleeding events than was aspirin (8.7%; difference, 13.3% [95% CI, 8.6% to 18.0%]; OR, 2.98 [95% CI, 1.99 to 4.47]; P < .001), but not BARC type 3 or 5 bleeding events (1.8% vs 1.8%, difference, 0% [95% CI, -1.8% to 1.8%]; OR, 1.00 [95% CI, 0.37 to 2.69]; P = .99). Compared with aspirin, ticagrelor monotherapy was not significantly associated with saphenous vein graft failure (19.3% vs 21.7%, difference, -2.6% [95% CI, -9.1% to 3.9%]; OR, 0.86 [95% CI, 0.58 to 1.27]; P = .44) or BARC type 2, 3, or 5 bleeding events (8.9% vs 7.3%, difference, 1.7% [95% CI, -2.8% to 6.1%]; OR, 1.25 [95% CI, 0.69 to 2.29]; P = .46). Conclusions and Relevance: Among patients undergoing coronary artery bypass graft surgery, adding ticagrelor to aspirin was associated with a significantly decreased risk of vein graft failure. However, this was accompanied by a significantly increased risk of clinically important bleeding.

Outcomes of coronary artery bypass grafting in patients with human immunodeficiency virus infection.

BACKGROUND: With early and effective antiretroviral therapy and improved survival for persons living with human immunodeficiency virus infection (PLHIV), this patient population now faces an increasingly elevated risk of cardiovascular disease. However, the data on outcomes after coronary artery bypass grafting (CABG) for revascularization of coronary artery disease (CAD) in HIV+ patients is limited. METHODS: We conducted a retrospective analysis of 16 patients undergoing isolated CABG at the Medical University of Vienna from 2005 to 2018, who were HIV+ on admission. The primary endpoint of the study was survival. Secondary endpoints included the components of major adverse cardiac and cerebrovascular events (MACCE): cardiovascular death, stroke, myocardial infarction (MI), and repeat revascularization. RESULTS: Patients were followed for a median of 49 months (range, 7-142 months). Survival was 100% and 90% at 1 and 3 years after CABG, respectively. There were no strokes. MI and subsequent repeat revascularization were observed in two patients. CONCLUSION: CABG provides excellent short- and midterm survival and freedom from MACCE in HIV+ patients with CAD requiring revascularization.

Randomized trial of ticagrelor vs. aspirin in patients after coronary artery bypass grafting: the TiCAB trial.

AIMS: The antiplatelet treatment strategy providing optimal balance between thrombotic and bleeding risks in patients undergoing coronary artery bypass grafting (CABG) is unclear. We prospectively compared the efficacy of ticagrelor and aspirin after CABG. METHODS AND RESULTS: We randomly assigned in double-blind fashion patients scheduled for CABG to either ticagrelor 90 mg twice daily or 100 mg aspirin (1:1) once daily. The primary outcome was the composite of cardiovascular death, myocardial infarction (MI), repeat revascularization, and stroke 12 months after CABG. The main safety endpoint was based on the Bleeding Academic Research Consortium classification, defined as BARC ≥4 for periprocedural and hospital stay-related bleedings and BARC ≥3 for post-discharge bleedings. The study was prematurely halted after recruitment of 1859 out of 3850 planned patients. Twelve months after CABG, the primary endpoint occurred in 86 out of 931 patients (9.7%) in the ticagrelor group and in 73 out of 928 patients (8.2%) in the aspirin group [hazard ratio 1.19; 95% confidence interval (CI) 0.87-1.62; P = 0.28]. All-cause mortality (ticagrelor 2.5% vs. aspirin 2.6%, hazard ratio 0.96, CI 0.53-1.72; P = 0.89), cardiovascular death (ticagrelor 1.2% vs. aspirin 1.4%, hazard ratio 0.85, CI 0.38-1.89; P = 0.68), MI (ticagrelor 2.1% vs. aspirin 3.4%, hazard ratio 0.63, CI 0.36-1.12, P = 0.12), and stroke (ticagrelor 3.1% vs. 2.6%, hazard ratio 1.21, CI 0.70-2.08; P = 0.49), showed no significant difference between the ticagrelor and aspirin group. The main safety endpoint was also not significantly different (ticagrelor 3.7% vs. aspirin 3.2%, hazard ratio 1.17, CI 0.71-1.92; P = 0.53). CONCLUSION: In this prematurely terminated and thus underpowered randomized trial of ticagrelor vs. aspirin in patients after CABG no significant differences in major cardiovascular events or major bleeding could be demonstrated. CLINICALTRIALS.GOV IDENTIFIER: NCT01755520.

A randomized, parallel group, double-blind study of ticagrelor compared with aspirin for prevention of vascular events in patients undergoing coronary artery bypass graft operation: Rationale and design of the Ticagrelor in CABG (TiCAB) trial: An Investigator-Initiated trial.

BACKGROUND: For patients with coronary artery disease undergoing coronary bypass surgery, acetylsalicylic acid (ASA) currently represents the gold standard of antiplatelet treatment. However, adverse cardiovascular event rates in the first year after coronary artery bypass grafting (CABG) still exceed 10%. Graft failure, which is predominantly mediated by platelet aggregation, has been identified as a major contributing factor in this context. Therefore, intensified platelet inhibition is likely to be beneficial. Ticagrelor, an oral, reversibly binding and direct-acting P2Y12 receptor antagonist, provides a rapid, competent, and consistent platelet inhibition and has shown beneficial results compared with clopidogrel in the subset of patients undergoing bypass surgery in a large previous trial. HYPOTHESIS: Ticagrelor is superior to ASA for the prevention of major cardiovascular events within 1 year after CABG. STUDY DESIGN: The TiCAB trial (NCT01755520) is a multicenter, phase III, double-blind, double-dummy, randomized trial comparing ticagrelor with ASA for the prevention of major cardiovascular events within 12 months after CABG. Patients undergoing CABG will be randomized in a 1:1 fashion to either ticagrelor 90 mg twice daily or ASA 100 mg once daily. The study medication will be started within 24 hours after surgery and maintained for 12 months. The primary end point is the composite of cardiovascular death, myocardial infarction, stroke, and repeat revascularization at 12 months after CABG. The sample size is based on an expected event rate of 13% of the primary end point within the first 12 months after randomization in the control group, a 2-sided α level of .0492 (to preserve the overall significance level of .05 after planned interim analysis), a power of 0.80%, 2-sided testing, and an expected relative risk of 0.775 in the active group compared with the control group and a dropout rate of 2%. According to power calculations based on a superiority design for ticagrelor, it is estimated that 3,850 patients should be enrolled. SUMMARY: There is clinical equipoise on the issue of optimal platelet inhibition after CABG. The TiCAB trial will provide a pivotal comparison of the efficacy and safety of ticagrelor compared with ASA after CABG.

Outcomes by sex in the International Study of Comparative Health Effectiveness With Medical and Invasive Approaches (ISCHEMIA) trial.

BACKGROUND: In the International Study of Comparative Health Effectiveness With Medical and Invasive Approaches (ISCHEMIA) trial, among participants with stable coronary artery disease, the risk of cardiac events was similar between an invasive (INV) strategy of angiography and coronary revascularisation and a conservative (CON) strategy of initial medical therapy alone. Outcomes according to participant sex were not reported. AIMS: We aimed to analyse the outcomes of ISCHEMIA by participant sex. METHODS: We evaluated 1) the association between participant sex and the likelihood of undergoing revascularisation for participants randomised to the INV arm; 2) the risk of the ISCHEMIA primary composite outcome (cardiovascular death, any myocardial infarction [MI] or rehospitalisation for unstable angina, heart failure or resuscitated cardiac arrest) by participant sex; and 3) the contribution of the individual primary outcome components to the composite outcome by participant sex. RESULTS: Of 5,179 randomised participants, 1,168 (22.6%) were women. Female sex was independently associated with a lower likelihood of revascularisation when assigned to the INV arm (adjusted odds ratio 0.75, 95% confidence interval [CI]: 0.57-0.99; p=0.04). The INV versus CON effect on the primary composite outcome was similar between sexes (women: hazard ratio [HR] 0.96, 95% CI: 0.70-1.33; men: HR 0.90, 95% CI: 0.76-1.07; pinteraction=0.71). The contribution of the individual components to the composite outcome was similar between sexes except for procedural MI, which was significantly lower in women (9/151 [5.9%]) than men (67/519 [12.9%]; p=0.01). CONCLUSIONS: In ISCHEMIA, women assigned to the INV arm were less likely to undergo revascularisation than men. The effect of an INV versus CON strategy was consistent by sex, but women had a significantly lower contribution of procedural MI to the primary outcome.

Research Concepts and Opportunities for Early-Career Investigators in Cardiac Surgery.

Basic, translational or clinic, research is a key component of cardiac surgery. Understanding basic cellular and molecular mechanisms is key to improving patient outcomes, and cardiac surgical procedures must be compared with nonsurgical alternatives. However, guidance for early-career investigators interested in cardiac surgery research is limited. This opinion piece aims at providing basic guidance and principles based on the authors' experience.